| 摘要 |
PURPOSE:To form a separation membrane to the separation membrane forming surface of a nonwoven fabric in a hardly delaminated state, by applying calender processing to the nonwoven fabric at temp., which is set by adding a specific value to the glass transition temp. of the constitutional material of said nonwoven fabric, or less. CONSTITUTION:A nonwoven fabric comprising a polyethylene terephthalate fiber is processed to one having predetermined air permeability by using a calender roll heated to temp. not exceeding one set by adding about 20 deg.C to the glass transition temp. of said fiber not only to smooth the surface thereof but also to suppress the surface fluffing thereof. The support cloth for a separation membrane thus obtained by calender processing is formed into a tubular form for example and a polyether sulfone membrane is applied to the inner surface of the tube to form a separation membrane. Because the separation membrane of the nonwoven fabric is smooth but prevented from fluffing, the separation membrane having a uniform thickness is obtained. Because the surface of the nonwoven fabric does not become too dense, the delamination degree of the separation membrane can be kept in a practical range. |
